Compositions comprising sulfonamide material and processes for photolithography

ABSTRACT

New photoresist compositions are provided that are useful for immersion lithography. Preferred photoresist compositions of the invention comprise one or more materials that have sulfonamide substitution. Particularly preferred photoresists of the invention can exhibit reduced leaching of resist materials into an immersion fluid contacting the resist layer during immersion lithography processing.

This application claims the benefit of priority under 35 U.S.C. §119(e)to U.S. Provisional Application No. 61/199,666, filed Nov. 19, 2009, theentire contents of which application are incorporated herein byreference.

The present invention relates to new photoresist compositions that areparticularly useful in immersion lithography processes. Preferredphotoresist compositions of the invention comprise one or moresulfonamide-containing materials. Preferably, the one or moresulfonamide-containing materials can be substantially non-mixable with aseparate resin component of the resist. Particularly preferredphotoresists of the invention can exhibit reduced defects followingdevelopment with an aqueous alkaline solution.

Photoresists are photosensitive films used for transfer of an image to asubstrate. A coating layer of a photoresist is formed on a substrate andthe photoresist layer is then exposed through a photomask to a source ofactivating radiation. The photomask has areas that are opaque toactivating radiation and other areas that are transparent to activatingradiation. Exposure to activating radiation provides a photoinducedchemical transformation of the photoresist coating to thereby transferthe pattern of the photomask to the photoresist coated substrate.Following exposure, the photoresist is developed to provide a reliefimage that permits selective processing of a substrate. See U.S. PatentApplication Publication 2006/0246373.

The growth of the semiconductor industry is driven by Moore's law whichstates that the complexity of an IC device doubles on average every twoyears. This necessitates the need to lithographically transfer patternsand structures with ever decreasing feature size.

While currently available photoresists are suitable for manyapplications, current resists also can exhibit significant shortcomings,particularly in high performance applications such as formation ofhighly resolved sub-quarter micron and even sub-tenth micron features.

We now provide new photoresist compositions and processes. Photoresistcompositions comprise a material that comprises one or more sulfonamidegroups.

Preferred photoresist compositions may comprise one or more materialthat comprise optionally substituted sulfonamide groups, includinggroups such as RS(═O)(X)NR′₂ where R is a non-hydrogen substituent,particularly —OH (to provide —SO₃H), optionally substituted C₁₋₂₀alkyl,and an electron-withdrawing group such as halogen especially fluoro orhaloalkyl such as fluoroalkyl e.g. F₃C—. In the formula RS(═O)(X)NR′₂, Xis a spacer (e.g. a chemical bond or a 1 to 8 carbon linkage), and eachR′ is independently a hydrogen or non-hydrogen substituent such asoptionally substituted C₁₋₂₀alkyl including a group as defined for Rabove.

It thus should be understood that references herein to “sulfonamide” areinclusive of where a sulfono (SO₂) moiety is directly linked (e.g. X informula RS(═O)(X) NR′₂ is chemical bond) to nitrogen as well as where asulfono (SO₂) moiety is spaced by 1, 2, 3 or more atoms (such as carbonatoms, e.g. X in formula RS(═O)(X)NR′₂ is (—CH₂—)₁₋₃) from the nitrogenof the sulfonamide group.

In certain aspects of the invention, preferred are photoresistcompositions that comprise materials that comprise sulfonamide group(s)where a sulfono (SO₂) moiety is spaced by 1, 2, 3 or more non-nitrogenatoms from the most adjacent nitrogen of the sulfonamide moiety.

More particularly, preferred photoresists of the invention may comprise:

(i) one or more resins,

(ii) a photoactive component which may suitably comprise one or morephotoacid generator compounds, and

(iii) one or more materials that comprise sulfonamide substitution (suchmaterials sometimes referred to herein as “sulfonamide-substitutedmaterials,” or “sulfonamide materials” or other similar phrase).Preferably, the one or more materials that comprise sulfonamidesubstitution are substantially non-mixable with the one or more resins.

Particularly preferred photoresists of the invention can exhibit reduceddefects associated with a resist relief image formed from thephotoresist composition. In certain aspects, micro-bridging betweenlines of the formed resist relief image can be minimized or avoided.

As referred to herein, one or more materials that are substantiallynon-mixable with the one or more photoresist resins can be any materialadded to a photoresist that results in reduced defects upon aqueousalkaline development.

Suitable sulfonamide-substituted materials (including substantiallynon-mixable sulfonamide-substituted materials) for use in photoresistsof the invention include compositions that comprise silicon and/orfluorine substitution in addition to sulfonamide substitution.

Also preferred are those sulfonamide-substituted materials (includingsubstantially non-mixable sulfonamide-substituted materials) thatcontain photoacid-labile groups, such as photoacid-labile ester oracetal groups, including such groups as described herein employed in aresin component of a chemically amplified photoresist.

Preferred sulfonamide-substituted materials (including substantiallynon-mixable sulfonamide-substituted materials) for use in photoresistsof the invention also will be soluble in the same organic solvent(s)used to formulate the photoresist composition.

Particularly preferred sulfonamide materials (including substantiallynon-mixable materials) for use in photoresists of the invention alsowill have lower surface energy and/or smaller hydrodynamic volume thanthe one or more resins of the photoresist's resin component. The lowersurface energy can facilitate segregation or migration of thesubstantially non-mixable materials to top or upper portions of anapplied the photoresist coating layer. Additionally, relative smallerhigher hydrodynamic volume also can be preferred because it canfacilitate efficient migration (higher diffusion coefficient) of the oneor more substantially non-mixable materials to upper regions of theapplied photoresist coating layer.

Preferred sulfonamide materials (including substantially non-mixablesulfonamide-substituted materials) for use in photoresists of theinvention also will be soluble in photoresist developer compositions(e.g. 0.26N aqueous alkaline solution such as a 0.26N tetramethylammonium hydroxide aqueous developer). Thus, in addition tophotoacid-labile groups as discussed above, other aqueousbase-solubilizing groups may be included in the substantiallynon-mixable materials such as hydroxyl, fluoroalcohol (e.g.—C(OH)(CF₃)₂), carboxy and the like.

Suitable sulfonamide materials (including substantially non-mixablesulfonamide-substituted materials) for use in photoresists of theinvention also may be in the form of particles. Such particles mayinclude polymers that are polymerized in the form discrete particles,i.e. as separate and distinct polymer particles. Such polymer particlestypically have one or more different characteristics from linear orladder polymers such as linear or ladder silicon polymers. For example,such polymer particles may have a defined size and a low molecularweight distribution. More particularly, in a preferred aspect, aplurality of the polymer particles may be employed in a photoresist ofthe invention with a mean particle size (dimension) of from about 5 to3000 angstroms, more preferably from about 5 to 2000 angstroms, stillmore preferably from about 5 to about 1000 angstroms, yet morepreferably from about 10 to about 500 angstroms, even more preferablyfrom 10 to 50 or 200 angstroms. For many applications, particularlypreferred particles have a mean particle size of less than about 200 or100 angstroms.

Additional suitable sulfonamide materials (including substantiallynon-mixable sulfonamide-substituted materials) for use in photoresistsof the invention may have Si content, including silsesquioxanematerials, materials with SiO₂ groups, and the like.

Preferred silicon-containing substantially non-mixable materials alsoinclude polyhedral oligomeric silsesquioxanes.

Preferred imaging wavelengths of lithographic systems of the inventioninclude sub-300 nm wavelengths e.g. 248 nm, and sub-200 nm wavelengthse.g. 193 nm. In addition to one or more sulfonamide materials (includingsubstantially non-mixable sulfonamide-substituted materials),particularly preferred photoresists of the invention may contain aphotoactive component (e.g. one or more photoacid generator compounds)and one or more resins that are chosen from among:

1) a phenolic resin that contains acid-labile groups that can provide achemically amplified positive resist particularly suitable for imagingat 248 nm. Particularly preferred resins of this class include: i)polymers that contain polymerized units of a vinyl phenol and an alkylacrylate, where the polymerized alkyl acrylate units can undergo adeblocking reaction in the presence of photoacid. Exemplary alkylacrylates that can undergo a photoacid-induced deblocking reactioninclude e.g. t-butyl acrylate, t-butyl methacrylate, methyladamantylacrylate, methyl adamantyl methacrylate, and other non-cyclic alkyl andalicyclic acrylates that can undergo a photoacid-induced reaction, suchas polymers in U.S. Pat. Nos. 6,042,997 and 5,492,793, incorporatedherein by reference; ii) polymers that contain polymerized units of avinyl phenol, an optionally substituted vinyl phenyl (e.g. styrene) thatdoes not contain a hydroxy or carboxy ring substituent, and an alkylacrylate such as those deblocking groups described with polymers i)above, such as polymers described in U.S. Pat. No. 6,042,997,incorporated herein by reference; and iii) polymers that contain repeatunits that comprise an acetal or ketal moiety that will react withphotoacid, and optionally aromatic repeat units such as phenyl orphenolic groups; such polymers have been described in U.S. Pat. Nos.5,929,176 and 6,090,526, incorporated herein by reference, as well asblends of i) and/or ii) and/or iii);

2) phenolic resins that do not contain acid-labile groups such aspoly(vinylphenol) and novolak resins that may be employed in I-line andG-line photoresists together with a diazonaphthoquinone photoactivecompound and have been described e.g. in U.S. Pat. Nos. 4,983,492;5,130,410; 5,216,111; and 5529880;

3) a resin that is substantially or completely free of phenyl or otheraromatic groups that can provide a chemically amplified positive resistparticularly suitable for imaging at sub-200 nm wavelengths such as 193nm. Particularly preferred resins of this class include: i) polymersthat contain polymerized units of a non-aromatic cyclic olefin(endocyclic double bond) such as an optionally substituted norbornene,such as polymers described in U.S. Pat. Nos. 5,843,624, and 6,048,664,incorporated herein by reference; ii) polymers that contain alkylacrylate units such as e.g. t-butyl acrylate, t-butyl methacrylate,methyladamantyl acrylate, methyl adamantyl methacrylate, and othernon-cyclic alkyl and alicyclic acrylates; such polymers have beendescribed in U.S. Pat. No. 6,057,083; European Published ApplicationsEP01008913A1 and EP00930542A1; and U.S. pending patent application Ser.No. 9/143,462, all incorporated herein by reference, and polymers thatcontain polymerized anhydride units, particularly polymerized maleicanhydride and/or itaconic anhydride units, such as disclosed in EuropeanPublished Application EP01008913A1 and U.S. Pat. No. 6,048,662, bothincorporated herein by reference, as well as blends of i) and/or ii)and/or iii);

4) a resin that contains repeat units that contain a hetero atom,particularly oxygen and/or sulfur (but other than an anhydride, i.e. theunit does not contain a keto ring atom), and preferable aresubstantially or completely free of any aromatic units. Preferably, theheteroalicyclic unit is fused to the resin backbone, and furtherpreferred is where the resin comprises a fused carbon alicyclic unitsuch as provided by polymerization of a norborene group and/or ananhydride unit such as provided by polymerization of a maleic anhydrideor itaconic anhydride. Such resins are disclosed in PCT/US01/14914 andU.S. application Ser. No. 09/567,634.

5) resins that contain Si-substitution including poly(silsesquioxanes)and the like and may be used with an undercoated layer. Such resins aredisclosed e.g. in U.S. Pat. No. 6,803,171.

6) a resin that contains fluorine substitution (fluoropolymer), e.g. asmay be provided by polymerization of tetrafluoroethylene, a fluorinatedaromatic group such as fluoro-styrene compound, compounds that comprisea hexafluoroalcohol moiety, and the like. Examples of such resins aredisclosed e.g. in PCT/US99/21912.

Preferred photoresists of the invention include bothchemically-amplified positive-acting and negative-acting photoresists.Typically preferred chemically-amplified positive resists include one ormore resins that comprise photoacid-labile groups such asphotoacid-labile ester or acetal groups.

The invention further provides methods for forming a photoresist reliefimage and producing an electronic device using photoresists of theinvention. The invention also provides novel articles of manufacturecomprising substrates coated with a photoresist composition of theinvention.

Other aspects of the invention are disclosed infra.

As discussed above, particularly preferred photoresists of the inventioncan exhibit reduced defects following aqueous alkaline development. Suchdefects can include reduced organic residues in areas bared ofphotoresist upon development as well as reduced microbridging betweenimages resist lines or other features.

As discussed above, suitable materials of photoresists of the inventionthat are substantially non-mixable with the resist resin component canbe readily identified by simple testing. In particular, as referred toherein, preferred substantially non-mixable materials will provide adecreased occurrence or amount of defects upon aqueous alkalinedevelopment relative to a comparable photoresist relative to the samephotoresist system that is processed into the same manner, but in theabsence of the candidate substantially non-mixable material(s).Assessment of defects (or absence thereof) can be made via scanningelectron micrography. Detection of photoresist material in the immersionfluid can be conducted as described in Example 2 of U.S. PatentPublication 2006/0246373 and includes mass spectroscopy analysis of theimmersion fluid before and after exposure to the photoresist. In suchanalysis, the immersion fluid directly contacts the tested photoresistcomposition layer for about 60 seconds during exposure. Preferably,addition of one or more substantially non-mixable materials provides atleast a 10 percent reduction in photoresist material (again, acid ororganics as detected by mass spectroscopy) residing in the immersionfluid relative to the same photoresist that does not employ suchsubstantially non-mixable material(s), more preferably the one or moresubstantially non-mixable materials provides at least a 20, 50, or 100,200, 500, or 1000 percent reduction photoresist material (again, acidand/or organics) residing in to the immersion fluid relative to the samephotoresist that does not contain the substantially non-mixablematerial(s).

Preferred photoresists of the invention will result in less than1.6×E-10 (mole/cm²/sec) of photoacid generator material being leachedinto deionized water or other overcoating immersion fluid for 60 secondsduring exposure by the analysis method described in Example 2 of U.S.Patent Publication 2006/0246373.

Preferred photoresists of the invention may have preferred water contactangles. As referred to herein, water contact angles, such as static,receding, advancing sliding, developer static can be determined inaccordance with the producers disclosed in Burnett et al., J. Vac. Sci.Techn. B, 23(6), pages 2721-2727 (November/December 2005). Preferredphotoresists (as determined as a spin-coated layer with solvent removedby soft-bake) will have a receding angle of at least 65°, morepreferably at least 70°. Additionally, preferred substantiallynon-mixable materials (as determined as a spin-coated layer with solventremoved by soft-bake) will have a receding angle of at least 65°, morepreferably at least 70°.

Particularly preferred sulfonamide materials (including substantiallynon-mixable sulfonamide-substituted materials) are resins and includehigher order polymers e.g. copolymers, terpolymers, tetrapolymers andpentapolymers. Particularly preferred are such polymers that comprisefluorine substitution in addition to sulfonamide substitution. Preferredfluoro substitution include perfluoro groups e.g. F₃C—, F₃CCF₂—, andfluorinated alcohols e.g. (F₃C)₂C(OH)—.

Specifically preferred sulfonamide resins for use in photoresists of theinvention include the following:

As discussed above, suitable sulfonamide materials (includingsubstantially non-mixable sulfonamide-substituted materials) includeSi-containing materials. Especially preferred sulfonamide materials(including substantially non-mixable sulfonamide-substituted materials)substantially non-mixable materials include nanostructured compositions,which are commercially available from groups such as Hybrid Plastics(Fountain Valley, Calif.), Sigma/Aldrich, and others. Such materials mayinclude molecular silicas which have a Si—O core enveloped by organicgroups; silanols; and polymers and resins which include silsesquioxanecage-structured compounds and may be silicones, styrenics, acrylics,alicyclics such as norbornenes and others.

Particles (including organic particles) useful as sulfonamide materials(including substantially non-mixable sulfonamide-substituted materials)include Si-containing and fluorinated materials that have sulfonamidesubstitution. Such particles are commercially available, or can bereadily synthesized, e.g. by reaction of one or more monomers togetherwith a crosslinking agent and an initiator compound if desired. Thereacted monomers may have substitution as desired e.g. fluorine, Sigroups, photoacid-labile groups such as photoacid-labile esters oracetals, other base-solubilizing groups such as alcohols and the like.See Example 1 which follows for an exemplary synthesis of such particlesproduced with multiple distinct monomers, where one of the monomersprovides a photoacid-labile group to the resulting polymer particle.

The sulfonamide materials (including substantially non-mixablesulfonamide-substituted materials) may be present in a photoresistcomposition in relatively small amounts and still provide effectiveresults. For instance, the one or more sulfonamide-substituted materials(including substantially non-mixable sulfonamide-substituted materials)may be suitable present in about 0.1 to 20 weight percent based on totalweight of a fluid photoresist composition. Suitable amounts also areprovided in the examples which follow.

As discussed, various moieties of sulfonamide materials and othercomponents of photoresists of the invention. A “substituted” substituentmay be substituted at one or more available positions, typically 1, 2,or 3 positions by one or more suitable groups such as e.g. halogen(particularly F, Cl or Br); cyano; C₁₋₈ alkyl; C₁₋₈ alkoxy; C₁₋₈alkylthio; C₁₋₈ allylsulfonyl; C₂₋₈ alkenyl; C₂₋₈ alkynyl; hydroxyl;nitro; carbocyclic aryl such as phenyl, napthyl, acenaphthyl,anthracenyl; alkanoyl such as a C₁₋₆ alkanoyl e.g. acyl and the like;etc.

In certain aspects of the invention, excluded are photoresists thatcontain a fluorinated surfactant material where the surfactant materialcontains from 30 to 60 mass % of fluorine atoms, or even 20 mass %fluorine atoms, or up to 70 mass percent fluorine atoms.

In additional certain aspects of the invention, excluded arephotoresists that comprise a sulfonamide-containing resin that containsa total of only two distinct repeat units. In such aspects, suitable maybe photoresists that comprise a sulfonamide-containing resin thatcontains a three, four, five or more distinct repeat units (i.e.terpolymers, terapolymers, pentapOlymers and other higher order polymersthat comprise sulfonamide substitution.

In additional other aspects of the invention, excluded are photoresiststhat comprise a sulfonamide-containing resin that comprise a polymerizedrepeat that contains a structure of (RCH═CH)C(═O)OCH(CF₃)₂ where R is Hor CH₃.

In additional other aspects of the invention, excluded are photoresiststhat comprise a sulfonamide-containing resin that comprise a polymerizedrepeat that contains a structure of(RCH═CH)C(═O)OCH(cyclohexyl)CH₂C(OH)(CF₃)₂ where R is H or CH₃.

In certain other aspects of the invention, excluded are photoresiststhat comprise a material that contains a sulfonamide group of thestructure —NHS(O₂)CF₃.

As discussed above, preferred photoresists for use in accordance withthe invention include positive-acting or negative-acting chemicallyamplified photoresists, i.e. negative-acting resist compositions whichundergo a photoacid-promoted crosslinking reaction to render exposedregions of a coating layer of the resist less developer soluble thanunexposed regions, and positive-acting resist compositions which undergoa photoacid-promoted deprotection reaction of acid labile groups of oneor more composition components to render exposed regions of a coatinglayer of the resist more soluble in an aqueous developer than unexposedregions. Ester groups that contain a tertiary non-cyclic alkyl carbon(e.g. t-butyl) or a tertiary alicyclic carbon (e.g. methyladamantyl)covalently linked to the carboxyl oxygen of the ester are oftenpreferred photoacid-labile groups of resins employed in photoresists ofthe invention. Acetal photoacid-labile groups also will be preferred.

Preferred photoresists of the invention typically comprise a resincomponent and a photoactive component. Preferably the resin hasfunctional groups that impart alkaline aqueous developability to theresist composition. For example, preferred are resin binders thatcomprise polar functional groups such as hydroxyl or carboxylate.Preferably a resin component is used in a resist composition in anamount sufficient to render the resist developable with an aqueousalkaline solution.

For imaging at wavelengths greater than 200 nm, such as 248 nm, phenolicresins are typically preferred. Preferred phenolic resins are poly(vinylphenols) which may be formed by block polymerization, emulsionpolymerization or solution polymerization of the corresponding monomersin the presence of a catalyst. Vinylphenols useful for the production ofpolyvinyl phenol resins may be prepared, for example, by hydrolysis ofcommercially available coumarin or substituted coumarin, followed bydecarboxylation of the resulting hydroxy cinnamic acids. Usefulvinylphenols may also be prepared by dehydration of the correspondinghydroxy alkyl phenols or by decarboxylation of hydroxy cinnamic acidsresulting from the reaction of substituted or nonsubstitutedhydroxybenzaldehydes with malonic acid. Preferred polyvinylphenol resinsprepared from such vinylphenols have a molecular weight range of fromabout 2,000 to about 60,000 daltons.

Also preferred for imaging at wavelengths greater than 200 nm, such as248 nm are chemically amplified photoresists that comprise in admixturea photoactive component and a resin component that comprises a copolymercontaining both phenolic and non-phenolic units. For example, onepreferred group of such copolymers has acid labile groups substantially,essentially or completely only on non-phenolic units of the copolymer,particularly alkylacrylate photoacid-labile groups, i.e. aphenolic-alkyl acrylate copolymer. One especially preferred copolymerbinder has repeating units x and y of the following formula:

wherein the hydroxyl group be present at either the ortho, meta or parapositions throughout the copolymer, and R′ is substituted orunsubstituted alkyl having 1 to about 18 carbon atoms, more typically 1to about 6 to 8 carbon atoms. Tert-butyl is a generally preferred R′group. An R′ group may be optionally substituted by e.g. one or morehalogen (particularly F, Cl or Br), C₁₋₈ alkoxy, C₂₋₈ alkenyl, etc. Theunits x and y may be regularly alternating in the copolymer, or may berandomly interspersed through the polymer. Such copolymers can bereadily formed. For example, for resins of the above formula, vinylphenols and a substituted or unsubstituted alkyl acrylate such ast-butylacrylate and the like may be condensed under free radicalconditions as known in the art. The substituted ester moiety, i.e.R′—O—C(═O)—, moiety of the acrylate units serves as the acid labilegroups of the resin and will undergo photoacid induced cleavage uponexposure of a coating layer of a photoresist containing the resin.Preferably the copolymer will have a M_(w) of from about 8,000 to about50,000, more preferably about 15,000 to about 30,000 with a molecularweight distribution of about 3 or less, more preferably a molecularweight distribution of about 2 or less. Non-phenolic resins, e.g. acopolymer of an alkyl acrylate such as t-butylacrylate ort-butylmethacrylate and a vinyl alicyclic such as a vinyl norbornanyl orvinyl cyclohexanol compound, also may be used as a resin binder incompositions of the invention. Such copolymers also may be prepared bysuch free radical polymerization or other known procedures and suitablywill have a M_(w) of from about 8,000 to about 50,000, and a molecularweight distribution of about 3 or less.

Other preferred resins that have acid-labile deblocking groups for usein a positive-acting chemically-amplified photoresist of the inventionhave been disclosed in European Patent Application 0829766A2 of theShipley Company (resins with acetal and ketal resins) and EuropeanPatent Application EP0783136A2 of the Shipley Company (terpolymers andother copolymers including units of 1) styrene; 2) hydroxystyrene; and3) acid labile groups, particularly alkyl acrylate acid labile groupssuch as t-butylacrylate or t-butylmethacrylate). In general, resinshaving a variety of acid labile groups will be suitable, such as acidsensitive esters, carbonates, ethers, imides, etc. The photoacid labilegroups will more typically be pendant from a polymer backbone, althoughresins that have acid labile groups that are integral to the polymerbackbone also may be employed.

As discussed above, for imaging at sub-200 nm wavelengths such as 193nm, preferably a photoresist is employed that contains one or morepolymers that are substantially, essentially or completely free ofphenyl or other aromatic groups. For example, for sub-200 nm imaging,preferred photoresist polymers contain less than about 5 mole percentaromatic groups, more preferably less than about 1 or 2 mole percentaromatic groups, more preferably less than about 0.1, 0.02, 0.04 and0.08 mole percent aromatic groups and still more preferably less thanabout 0.01 mole percent aromatic groups. Particularly preferred polymersare completely free of aromatic groups. Aromatic groups can be highlyabsorbing of sub-200 nm radiation and thus are undesirable for polymersused in photoresists imaged with such short wavelength radiation.

Suitable polymers that are substantially or completely free of aromaticgroups and may be formulated with a PAG of the invention to provide aphotoresist for sub-200 nm imaging are disclosed in European applicationEP930542A1 and U.S. Pat. Nos. 6,692,888 and 6,680,159, all of theShipley Company.

Suitable polymers that are substantially or completely free of aromaticgroups suitably contain acrylate units such as photoacid-labile acrylateunits as may be provided by polymerization of methyladamanatylacrylate,methyladamantylmethacrylate, ethylfenchylacrylate,ethylfenchylmethacrylate, and the like; fused non-aromatic alicyclicgroups such as may be provided by polymerization of a norbornenecompound or other alicyclic compound having an endocyclic carbon-carbondouble bond; an anhydride such as may be provided by polymerization ofmaleic anhydride and/or itaconic anhydride; and the like.

Preferred negative-acting compositions of the invention comprise one ormore materials (such as a crosslinker component e.g. an amine-basedmaterials such as a melamine resin) that will cure, crosslink or hardenupon exposure to acid, and a photoactive component of the invention.Particularly preferred negative acting compositions comprise a resinbinder such as a phenolic resin, a crosslinker component and aphotoactive component of the invention. Such compositions and the usethereof has been disclosed in European Patent Applications 0164248 and0232972 and in U.S. Pat. No. 5,128,232 to Thackeray et al. Preferredphenolic resins for use as the resin binder component include novolaksand poly(vinylphenol)s such as those discussed above. Preferredcrosslinkers include amine-based materials, including melamine,glycolurils, benzoguanamine-based materials and urea-based materials.Melamine-formaldehyde resins are generally most preferred. Suchcrosslinkers are commercially available, e.g. the melamine resins soldby Cytec under the trade names Cymel 300, 301 and 303. Glycoluril resinsare sold by Cytec under trade names Cymel 1170, 1171, 1172, urea-basedresins are sold under the trade names of Beetle 60, 65 and 80, andbenzoguanamine resins are sold under the trade names Cymel 1123 and1125.

For imaging at sub-200 nm wavelengths such as 193 nm, preferrednegative-acting photoresists are disclosed in WO 03077029 to the ShipleyCompany.

Photoresists of the invention also may contain other materials. Forexample, other optional additives include actinic and contrast dyes,anti-striation agents, plasticizers, speed enhancers, sensitizers (e.g.for use of a PAG of the invention at longer wavelengths such as I-line(i.e. 365 nm) or G-line wavelengths), etc. Such optional additivestypically will be present in minor concentration in a photoresistcomposition except for fillers and dyes which may be present inrelatively large concentrations such as, e.g., in amounts of from 5 to30 percent by weight of the total weight of a resist's dry components.

A preferred optional additive of resists of the invention is an addedbase, e.g. a caprolactam, which can enhance resolution of a developedresist relief image. The added base is suitably used in relatively smallamounts, e.g. about 1 to 10 percent by weight relative to the PAG, moretypically 1 to about 5 weight percent. Other suitable basic additivesinclude ammonium sulfonate salts such as piperidinium p-toluenesulfonateand dicyclohexylammonium p-toluenesulfonate; alkyl amines such astripropylamine and dodecylamine; aryl amines such as diphenylamine,triphenylamine, aminophenol,2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, etc.

The resin component of resists of the invention is typically used in anamount sufficient to render an exposed coating layer of the resistdevelopable such as with an aqueous alkaline solution. Moreparticularly, a resin binder will suitably comprise 50 to about 90weight percent of total solids of the resist. The photoactive componentshould be present in an amount sufficient to enable generation of alatent image in a coating layer of the resist. More specifically, thephotoactive component will suitably be present in an amount of fromabout 1 to 40 weight percent of total solids of a resist. Typically,lesser amounts of the photoactive component will be suitable forchemically amplified resists.

The resist compositions of the invention also comprise a photoacidgenerator (i.e. “PAG”) that is suitably employed in an amount sufficientto generate a latent image in a coating layer of the resist uponexposure to activating radiation. Preferred PAGs for imaging at 193 nmand 248 nm imaging include imidosulfonates such as compounds of thefollowing formula:

wherein R is camphor, adamantane, alkyl (e.g. C₁₋₁₂ alkyl) andperfluoroalkyl such as perfluoro(C₁₋₁₂alkyl), particularlyperfluorooctanesulfonate, perfluorononanesulfonate and the like. Aspecifically preferred PAG isN-[(perfluorooctanesulfonyl)oxy]-5-norbornene-2,3-dicarboximide.

Sulfonate compounds are also suitable PAGs, particularly sulfonatesalts. Two suitable agents for 193 nm and 248 nm imaging are thefollowing PAGS 1 and 2:

Such sulfonate compounds can be prepared as disclosed in European PatentApplication 96118111.2 (publication number 0783136), which details thesynthesis of above PAG 1.

Also suitable are the above two iodonium compounds complexed with anionsother than the above-depicted camphorsulfonate groups. In particular,preferred anions include those of the formula RSO₃— where R isadamantane, alkyl (e.g. C₁₋₁₂ alkyl) and perfluoroalkyl such asperfluoro (C₁₋₁₂ alkyl), particularly perfluorooctanesulfonate,perfluorobutanesulfonate and the like.

Other known PAGS also may be employed in photoresists used in accordancewith the invention. Particularly for 193 nm imaging, generally preferredare PAGS that do not contain aromatic groups, such as theabove-mentioned imidosulfonates, in order to provide enhancedtransparency.

Photoresists of the invention also may contain other optional materials.For example, other optional additives include anti-striation agents,plasticizers, speed enhancers, etc. Such optional additives typicallywill be present in minor concentrations in a photoresist compositionexcept for fillers and dyes which may be present in relatively largeconcentrations, e.g., in amounts of from about 5 to 30 percent by weightof the total weight of a resist's dry components.

The photoresists used in accordance with the invention are generallyprepared following known procedures. For example, a resist of theinvention can be prepared as a coating composition by dissolving thecomponents of the photoresist in a suitable solvent such as, e.g., aglycol ether such as 2-methoxyethyl ether (diglyme), ethylene glycolmonomethyl ether, propylene glycol monomethyl ether; propylene glycolmonomethyl ether acetate; lactates such as ethyl lactate or methyllactate, with ethyl lactate being preferred; propionates, particularlymethyl propionate, ethyl propionate and ethyl ethoxy propionate; aCellosolve ester such as methyl Cellosolve acetate; an aromatichydrocarbon such toluene or xylene; or a ketone such as methylethylketone, cyclohexanone and 2-heptanone. Typically the solids content ofthe photoresist varies between 5 and 35 percent by weight of the totalweight of the photoresist composition. Blends of such solvents also aresuitable.

Liquid photoresist compositions may be applied to a substrate such as byspinning, dipping, roller coating or other conventional coatingtechnique. When spin coating, the solids content of the coating solutioncan be adjusted to provide a desired film thickness based upon thespecific spinning equipment utilized, the viscosity of the solution, thespeed of the spinner and the amount of time allowed for spinning.

Photoresist compositions used in accordance with the invention aresuitably applied to substrates conventionally used in processesinvolving coating with photoresists. For example, the composition may beapplied over silicon wafers or silicon wafers coated with silicondioxide for the production of microprocessors and other integratedcircuit components. Aluminum-aluminum oxide, gallium arsenide, ceramic,quartz, copper, glass substrates and the like are also suitablyemployed. Photoresists also may be suitably applied over anantireflective layer, particularly an organic antireflective layer.

Following coating of the photoresist onto a surface, it may be dried byheating to remove the solvent until preferably the photoresist coatingis tack free.

The photoresist layer (with overcoated barrier composition layer, ifpresent) in then exposed in an immersion lithography system, i.e. wherethe space between the exposure tool (particularly the projection lens)and the photoresist coated substrate is occupied by an immersion fluid,such as water or water mixed with one or more additives such as cesiumsulfate which can provide a fluid of enhanced refractive index.Preferably the immersion fluid (e.g.; water) has been treated to avoidbubbles, e.g. water can be degassed to avoid nanobubbles.

References herein to “immersion exposing” or other similar termindicates that exposure is conducted with such a fluid layer (e.g. wateror water with additives) interposed between an exposure tool and thecoated photoresist composition layer.

The photoresist composition layer is then suitably patterned exposed toactivating radiation with the exposure energy typically ranging fromabout 1 to 100 mJ/cm², dependent upon the exposure tool and thecomponents of the photoresist composition. References herein to exposinga photoresist composition to radiation that is activating for thephotoresist indicates that the radiation is capable of forming a latentimage in the photoresist such as by causing a reaction of thephotoactive component (e.g. producing photoacid from the photoacidgenerator compound).

As discussed above, photoresist compositions are preferablyphotoactivated by a short exposure wavelength, particularly a sub-400nm, sub-300 and sub-200 nm exposure wavelength, with I-line (365 nm),248 nm and 193 nm being particularly preferred exposure wavelengths aswell as EUV and 157 nm.

Following exposure, the film layer of the composition is preferablybaked at temperatures ranging from about 70° C. to about 160° C.Thereafter, the film is developed, preferably by treatment with anaqueous based developer such as quaternary ammonium hydroxide solutionssuch as a tetra-alkyl ammonium hydroxide solution; various aminesolutions preferably a 0.26 N tetramethylammonium hydroxide, such asethyl amine, n-propyl amine, diethyl amine, di-n-propyl amine, triethylamine, or methyldiethyl amine; alcohol amines such as diethanol amine ortriethanol amine; cyclic amines such as pyrrole, pyridine, etc. Ingeneral, development is in accordance with procedures recognized in theart.

Following development of the photoresist coating over the substrate, thedeveloped substrate may be selectively processed on those areas bared ofresist, for example by chemically etching or plating substrate areasbared of resist in accordance with procedures known in the art. For themanufacture of microelectronic substrates, e.g., the manufacture ofsilicon dioxide wafers, suitable etchants include a gas etchant, e.g. ahalogen plasma etchant such as a chlorine or fluorine-based etchant sucha Cl₂ or CF₄/CHF₃ etchant applied as a plasma stream. After suchprocessing, resist may be removed from the processed substrate usingknown stripping procedures.

All documents mentioned herein are incorporated herein by reference. Thefollowing non-limiting examples are illustrative of the invention. Alldocuments mentioned herein are incorporated by reference in theirentirety.

EXAMPLE 1 Sulfonamide Resin Preparation

A sulfonamide copolymer resin having the following structure wasprepared as described below:

A. Monomer and initiator mixture: weigh 7.00 g ofCH₃(CH═CH)C(═O)OCH(CH₃)CH₂C(CH₃)₂OH (the first monomer), 2.80 g of(CH₂═CH)C(═O)OC(CH₂)₂NHSO₂CF₃ (the second monomer) 0.42 g of Trignox-23(initiator) and 17.0 g PGMEA (solvent) into a feeding vial.B. Reactor: 30 g of PGMEA in a reactor and maintain at 85° C.C. Feed A into B: A is fed into B with a constant feeding rate in 120minutes.D. Holding temperature: after feeding A into B, the temperature of thereactor is maintained at 85° C. for additional two hrs, then allow thereactor temp to cool down naturally to room temperature.

The sulfonamide resin from the reactor can be used in a photoresistcomposition without further purification.

EXAMPLE 2 Additional Sulfonamide Resin Preparation

By procedures similar to those of Example 1, the following sulfonamideresin is prepared:

EXAMPLE 3 Photoresist Preparation and Processing

A photoresist composition is prepared by admixing the followingmaterials in the specified amounts:

1. Resin component: Terpolymer of (2-methyl-2-adamantylmethacrylate/beta-hydroxy-gamma-butyrolactonemethacrylate/cyano-norbornyl methacrylate in an amount of 6.79 weight %based on total weight of the photoresist composition;

2. Photoacid generator compound: T-butyl phenyl tetramethylene sulfoniumperfluorobutanesulfonate in an amount of 0.284 weight % based on totalweight of the photoresist composition;

3. Base additive: N-Alkyl Caprolactam in an amount of 0.017 weight %based on total weight of the photoresist composition;

4. Surfactant: R08 (fluorine-containing surfactant, available fromDainippon Ink & Chemicals, Inc.) in an amount of 0.0071 weight % basedon total weight of the photoresist composition

5. Substantially non-mixable additive: Polymer of Example 1 prepared asdescribed in Example 1 above and in an amount of 0.213 weight % based ontotal weight of the photoresist composition.

6. Solvent component: propylene glycol monomethyl ether acetate toprovide about a 90 percent fluid composition.

This photoresist composition containing is spin-coated onto siliconwafers, dried on vacuum hotplate to remove soft-plate and then exposedin an immersion lithography process with aqueous immersion fluiddirectly contacting the dried photoresist layers. In that immersionsystem, the photoresist layers is exposed to patterned 193 nm radiationat a dose of 24.1 mJ/cm².

The photoresist layers is then post-exposed baked (such as at about 120°C.) and developed with 0.26N alkaline aqueous developer solution.

To evaluate leaching of resist components after the post-exposure bakeand before development, the immersion fluid is evaluated for thephotoacid in the resist and its photo-degradation byproducts by LC/massspectroscopy (60 second leaching time tested).

What is claimed is:
 1. A method for processing a photoresistcomposition, comprising; (a) applying on a substrate a photoresistcomposition comprising: (i) one or more resins, (ii) a photoactivecomponent, and (iii) one or more resins that comprise a group of theformula RS(═O)₂—X—NR′₂, wherein X is a group with 1 to 8 carbon atoms, Ris a non-hydrogen substituent, and the groups R′ are each independentlya hydrogen atom or a non-hydrogen substituent, thereby forming aphotoresist layer, wherein the (iii) one or more resins aresubstantially non-mixable with the (i) one or more resins; and (b)immersion exposing the photoresist layer to radiation activating for thephotoresist composition.
 2. The method of claim 1 wherein the (iii) oneor more resins further comprise one or more electron-withdrawingmoieties.
 3. The method of claim 1 wherein the (iii) one or more resinscomprise one or more fluorine atoms or fluorine-substituted groups. 4.The method of claim 1 wherein the (iii) one or more resins compriseaqueous base-solubilizing groups and/or one or more photoacid-labilegroups.
 5. The method of claim 1 wherein the (iii) one or more resinscomprise one or more photoacid-labile groups.
 6. The method of claim 1,wherein X is (CH₂)₁₋₃.
 7. The method of claim 1, wherein R is —OH.
 8. Amethod for processing a photoresist composition, comprising: (a)applying on a substrate a photoresist composition comprising: (i) one ormore resins, (ii) a photoactive component, and (iii) one or more resinsthat comprise 1) a group of the formula RS(═O)₂—X—NR′₂, wherein X is agroup with 1 to 8 carbon atoms, R is a non-hydrogen substituent, and thegroups R′ are each independently a hydrogen atom or a non-hydrogensubstituent, 2) one or more fluorine groups or fluorine-substitutedgroups, and 3) one or more photoacid-labile groups, thereby forming aphotoresist layer, wherein the (iii) one or more resins aresubstantially non-mixable with the (i) one or more resins; and (b)immersion exposing the photoresist layer to radiation activating for thephotoresist composition.
 9. The method of claim 8 wherein the (iii) oneor more resins further comprise one or more electron-withdrawingmoieties.
 10. The method of claim 8 wherein the (iii) one or more resinscomprise aqueous base-solubilizing groups.
 11. The method of claim 8,wherein X is (CH₂)₁₋₃.
 12. The method of claim 8, wherein R is —OH.